In eddy current and some other types of testing, a sensor probe is contacted to a surface of an article to be tested. A sensor contained within the probe performs the test sensing while the probe is contacted to the surface. The data collected is used to assess the structural nature of the article. In one application of particular interest, eddy current measurements are used to assess whether small cracks, microstructural irregularities, and/or other types of irregularities are present in the article, which could lead to premature failure of the article.
Relatively small, hand-held sensor probes are conveniently employed to study irregularly shaped articles, for quick looks at articles, or in field situations where a larger apparatus cannot be readily provided. When a hand-held sensor probe is used, great care must be taken so that the sensor probe is positioned precisely relative to the surface of the article. Mispositioning may lead to attenuation of the signal that is to be measured by the sensor and/or to erroneous readings.
The operator of the sensor probe must maintain the proper positioning. One approach is to use fixturing to hold the sensor probe in the correct position relative to the article surface. The fixturing is time-consuming to set up, and in most cases is not compatible with the sensing of highly irregular articles, quick studies, and many field situations. In current practice, then, the usual approach is to scan the hand-held sensor probe over the surface many times while watching an indicator of the sensor data, until a judgment is made that sufficient sensor data of acceptable quality has been obtained. There are sometimes problems in knowing when a sufficient amount of information has been gathered, and knowing whether the information is accurate. The process of data taking is therefore dependent upon the skill and state of mind of the operator.
There is therefore a need for an approach to facilitate the taking of data using sensor probes that contact the surface of an article. The present invention fulfills this need, and further provides related advantages.